Athermal critical stresses for dislocation propagation in nanocrystalline aluminium
Christian Brandl, Shreevant Tiwari, Peter M Derlet, Helena Van Swygenhoven
PHILOSOPHICAL MAGAZINE | TAYLOR & FRANCIS LTD | Published : 2010
Molecular dynamics simulations investigating the mechanical properties of nanocrystalline Al have revealed the importance of both dislocation nucleation at grain boundaries and subsequent propagation as possible rate-limiting microscopic plastic process. Here, we present an approach to determine the athermal stress-strain behaviour of selected dislocations as they propagate within the nanocrystalline environment. In the first case study, the critical resolved shear stress to depin resulting into a planar propagation is found to be 735 MPa. In a second case study, a pinned dislocation is found to cross-slip at a critical resolved shear stress of 372 MPa to circumvent a near unfavoured grain b..View full abstract
Awarded by European Commission
The authors acknowledge the financial support of the European Commission (FP6-NANOMESO, Grant No. 016710). CB thanks Ju Li for initial discussions.